Orbital Environment Shell Models to Support Compliance with UN Sustainable Development Goals

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Earth observation (EO) missions can contribute towards the UN Sustainable Development Goals (SDGs) such as analysing farmland for ‘zero hunger’, bodies of water for ‘clean water and sanitation’ and land area for ‘life on land’. To achieve these observation missions, however, satellites may need to operate in similar orbit regimes, detracting from the sustainability of the space environment, leading to orbital congestion and potential collisions which can be counterproductive for other goals such as ‘responsible consumption and production’. Multiple companies are planning to launch large constellations of hundreds or thousands of satellites in the next decade. This will increase congestion in low-Earth orbit (LEO) and the risk of collisions and debris generation. In response, models have been created to estimate LEO orbital collision rates. This paper describes a methodology to compare existing collision probability data against a satellite sensor’s EO capabilities, such as resolution and revisit time, by dividing orbital
regimes into discrete altitude bands called ‘shells’. This allows for trade-offs to be analysed for orbital shells in terms of suitability for EO data collection and collision risk. Resulting analysis identifies optimum regions for future
constellations to reduce the risk of overcrowding and collisions while increasing the benefit for sustainability. It is found that despite high congestion as of 2019, regions around 775km are ideal for Earth Observation when the changing landscape of the next ten years is considered, with sensors such as the MSI on Sentienl-2 being placed in the most optimal areas for SDG observation and that even when planned mega constellations are considered, the collision rate for this region remains relatively low at 0.048 collisions per year. The potential benefits and challenges of using other orbital regions are also discussed.
Original languageEnglish
Title of host publication74th International Astronautical Congress (IAC), Baku, Azerbaijan, 2-6 October 2023
Publication statusAccepted/In press - 15 Sept 2023


  • Earth Observation
  • Sustainable Development Goals
  • Collision
  • Spatial Resolution
  • Debris Mitigation


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